Trapping (sub-)Neptunes similar to TOI-216b at the inner disk rim Implications for the disk viscosity and the Neptunian desert

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F22%3A10456197" target="_blank" >RIV/00216208:11320/22:10456197 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=hYeymzpOSl" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=hYeymzpOSl</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202244461" target="_blank" >10.1051/0004-6361/202244461</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Trapping (sub-)Neptunes similar to TOI-216b at the inner disk rim Implications for the disk viscosity and the Neptunian desert

Popis výsledku v původním jazyce

Context. The occurrence rate of observed sub-Neptunes has a break at 0.1 au, which is often attributed to a migration trap at the inner rim of protoplanetary disks where a positive co-rotation torque prevents inward migration. Aims. We argue that conditions in inner disk regions are such that sub-Neptunes are likely to open gaps, lose the support of the co-rotation torque as their co-rotation regions become depleted, and the trapping efficiency then becomes uncertain. We study what it takes to trap such gap-opening planets at the inner disk rim. Methods. We performed 2D locally isothermal and non-isothermal hydrodynamic simulations of planet migration. A viscosity transition was introduced in the disk to (i) create a density drop and (ii) mimic the viscosity increase as the planet migrated from a dead zone towards a region with active magneto-rotational instability (MRI). We chose TOI-216b as a Neptune-like upper-limit test case, but we also explored different planetary masses, both on fixed and evolving orbits. Results. For planet-to-star mass ratios q similar or equal to (4-8) x 10(-5), the density drop at the disk rim becomes reshaped due to a gap opening and is often replaced with a small density bump centred on the planet&apos;s co-rotation. Trapping is possible only if the bump retains enough gas mass and if the co-rotation region becomes azimuthally asymmetric, with an island of librating streamlines that accumulate a gas overdensity ahead of the planet. The overdensity exerts a positive torque that can counteract the negative torque of spiral arms. Under suitable conditions, the overdensity turns into a Rossby vortex. In our model, efficient trapping depends on the alpha viscosity and its contrast across the viscosity transition. In order to trap TOI-216b, alpha(DZ) = 10(-3) in the dead zone requires alpha(MRI) greater than or similar to 5 x 10(-2) in the MRI-active zone. If alpha(DZ) = 5 x 10(-4), alpha(MRI) greater than or similar to 7.5 x 10(-2) is needed. Conclusions. We describe a new regime of a migration trap relevant for massive (sub-)Neptunes that puts valuable constraints on the levels of turbulent stress in the inner part of their natal disks.

Název v anglickém jazyce

Trapping (sub-)Neptunes similar to TOI-216b at the inner disk rim Implications for the disk viscosity and the Neptunian desert

Popis výsledku anglicky

Context. The occurrence rate of observed sub-Neptunes has a break at 0.1 au, which is often attributed to a migration trap at the inner rim of protoplanetary disks where a positive co-rotation torque prevents inward migration. Aims. We argue that conditions in inner disk regions are such that sub-Neptunes are likely to open gaps, lose the support of the co-rotation torque as their co-rotation regions become depleted, and the trapping efficiency then becomes uncertain. We study what it takes to trap such gap-opening planets at the inner disk rim. Methods. We performed 2D locally isothermal and non-isothermal hydrodynamic simulations of planet migration. A viscosity transition was introduced in the disk to (i) create a density drop and (ii) mimic the viscosity increase as the planet migrated from a dead zone towards a region with active magneto-rotational instability (MRI). We chose TOI-216b as a Neptune-like upper-limit test case, but we also explored different planetary masses, both on fixed and evolving orbits. Results. For planet-to-star mass ratios q similar or equal to (4-8) x 10(-5), the density drop at the disk rim becomes reshaped due to a gap opening and is often replaced with a small density bump centred on the planet&apos;s co-rotation. Trapping is possible only if the bump retains enough gas mass and if the co-rotation region becomes azimuthally asymmetric, with an island of librating streamlines that accumulate a gas overdensity ahead of the planet. The overdensity exerts a positive torque that can counteract the negative torque of spiral arms. Under suitable conditions, the overdensity turns into a Rossby vortex. In our model, efficient trapping depends on the alpha viscosity and its contrast across the viscosity transition. In order to trap TOI-216b, alpha(DZ) = 10(-3) in the dead zone requires alpha(MRI) greater than or similar to 5 x 10(-2) in the MRI-active zone. If alpha(DZ) = 5 x 10(-4), alpha(MRI) greater than or similar to 7.5 x 10(-2) is needed. Conclusions. We describe a new regime of a migration trap relevant for massive (sub-)Neptunes that puts valuable constraints on the levels of turbulent stress in the inner part of their natal disks.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

<a href="/cs/project/GM21-23067M" target="_blank" >GM21-23067M: Hydrodynamické interakce planet s protoplanetárními disky a původ těsných exoplanetárních soustav</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy &amp; Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

666

Číslo periodika v rámci svazku

říjen

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

20

Strana od-do

A63

Kód UT WoS článku

000865835600002

EID výsledku v databázi Scopus

2-s2.0-85141652300